Patient- and operator-related factors associated with successful Glidescope intubations: a prospective observational study in 742 patients

Impact of Videolaryngoscopy Expertise on First-Attempt Intubation Success in Critically Ill Patients

OBJECTIVES

The use of a videolaryngoscope in the ICU on the first endotracheal intubation attempt and intubation-related complications is controversial. The objective of this study was to evaluate the first intubation attempt success rate in the ICU with the McGrath MAC videolaryngoscope (Medtronic, Minneapolis, MN) according to the operators' videolaryngoscope expertise and to describe its association with the occurrence of intubation-related complications.

DESIGN

Observational study.

SETTING

Medical ICU.

SUBJECTS

Consecutive endotracheal intubations in critically ill patients.

INTERVENTIONS

Systematic use of the videolaryngoscope.

MEASUREMENTS AND MAIN OUTCOMES

We enrolled 202 consecutive endotracheal intubations. Overall first-attempt success rate was 126 of 202 (62%). Comorbidities, junior operator, cardiac arrest upon admission, and coma were associated with a lower first-attempt success rate. The first-attempt success rate was less than 50% in novice operators (1-5 previous experiences with videolaryngoscope, independently of airway expertise with direct laryngoscopies) and 87% in expert operators (> 15 previous experiences with videolaryngoscope). Multivariate analysis confirmed the association between specific skill training with videolaryngoscope and the first-attempt success rate. Severe hypoxemia and overall immediate intubation-related complications occurred more frequently in first-attempt failure intubations (24/76, 32%) than in first-attempt success intubations (14/126, 11%) (p < 0.001).

CONCLUSIONS

We report for the first time in the critically ill that specific videolaryngoscopy skill training, assessed by the number of previous videolaryngoscopies performed, is an independent factor of first-attempt intubation success. Furthermore, we observed that specific skill training with the McGrath MAC videolaryngoscope was fast. Therefore, future trials evaluating videolaryngoscopy in ICUs should consider the specific skill training of operators in videolaryngoscopy.

A deliberately restricted laryngeal view with the GlideScope® video laryngoscope is associated with faster and easier tracheal intubation when compared with a full glottic view: a randomized clinical trial

INTRODUCTION

During video laryngoscopy (VL) with angulated or hyper-curved blades, it is sometimes difficult to complete tracheal intubation despite a full view of the larynx. When using indirect VL, it has been suggested that it may be preferable to obtain a deliberately restricted view of the larynx to facilitate passage of the endotracheal tube. We used the GlideScope® GVL video laryngoscope (GVL) to test whether deliberately obtaining a restricted view would result in faster and easier tracheal intubation than with a full view of the larynx.

METHODS

We recruited 163 elective surgical patients and randomly allocated the participants to one of two groups: Group F, where a full view of the larynx was obtained and held during GVL-facilitated tracheal intubation, and Group R, with a restricted view of the larynx (< 50% of glottic opening visible). Study investigators experienced in indirect VL performed the intubations. The intubations were recorded and the video recordings were subsequently assessed for total time to intubation, ease of intubation using a visual analogue scale (VAS; where 0 = easy and 100 = difficult), first-attempt success rate, and oxygen saturation after intubation. Complications were also assessed.

RESULTS

The median [interquartile range (IQR)] time to intubation was faster in Group R than in Group F (27 [22-36] sec vs 36 [27-48] sec, respectively; median difference, 9 sec; 95% confidence interval [CI], 5 to 13; P < 0.001). The median [IQR] VAS rating for ease of intubation was also better in Group R than in Group F (14 [6-42) mm vs 50 mm [17-65], respectively; median difference, 20 mm; 95% CI, 10 to 31; P < 0.001). There was no difference between groups regarding the first-attempt success rate, oxygen saturation immediately after intubation, or complications.

CONCLUSIONS

Using the GVL with a deliberately restricted view of the larynx resulted in faster and easier tracheal intubation than with a full view and with no additional complications. Our study suggests that obtaining a full or Cormack-Lehane grade 1 view may not be desirable when using the GVL. This trial was registered at ClinicalTrials.gov: NCT02144207.

Defining and developing expertise in tracheal intubation using a GlideScope(®) for anaesthetists with expertise in Macintosh direct laryngoscopy: an in-vivo longitudinal study

Although videolaryngoscopy can provide excellent views of the laryngeal structures as both the primary method of tracheal intubation and as a rescue technique for difficult direct laryngoscopy, the existing literature is inadequate to define expertise or even competence. We observed the performance of nine trainees during 890 intubations, with an additional 72 intubations performed by expert anaesthetists used as a control group. Univariate and multivariate mixed-effects logistic regression models were applied to detect potential predictors of successful intubation and define the number of intubations necessary for a trainee to achieve expertise (> 90% probability of optimal performance). Optimal performance was predicted by single laryngoscope insertion (p < 0.001) and a Cormack and Lehane grade-1 view (p < 0.001), and not by normal lifting force applied to the device (p = 0.15), with expertise reached after 76 attempts. These results indicate that expertise in videolaryngoscopy requires prolonged training and practice.

Comparison of three tracheal intubation techniques in thyroid tumor patients with a difficult airway: a randomized controlled trial

OBJECTIVE

To investigate the effectiveness of the Shikani optical stylet (SOS) and GlideScope video laryngoscope (GVL) for tracheal intubation of thyroid tumor patients with a difficult airway.

SUBJECTS AND METHODS

One hundred and twenty thyroid tumor patients with a difficult airway, who were undergoing elective surgery requiring general anesthesia, were enrolled in the study. They were randomly allocated to 3 groups (n = 40 each) who underwent direct laryngoscopy (DL), SOS or GVL. The outcomes recorded were time to intubation, first-attempt success rate, mean artery pressure (MAP), heart rate (HR) and incidence of complications.

RESULTS

The mean time to intubation in the SOS group (group S; 42.4 ± 24.1 s) and the GLV group (group G; 29.8 ± 22.3 s) was significantly less than that in the DL group (group D) (68.8 ± 26.6 s). The first-attempt success rate in group S (90.0%) and group G (97.5%) was significantly higher than that in group D (75.0%; all p < 0.05). The HR and MAP at 1 min after intubation were lowest in group S (76.4 ± 9.2 beats/min and 12.9 ± 1.1 kPa), followed by group G (79.9 ± 9.3 beats/min and 13.0 ± 0.9 kPa) and then group D (90.4 ± 8.1 beats/min and 16.6 ± 1.2 kPa). The difference was statistically significant (all p < 0.05). The incidence of lip or mucosal trauma was lowest in group S, followed by group G and then group D.

CONCLUSION

The SOS and the GLV had advantages over the DL in the management of thyroid tumor patients with a difficult airway in terms of a shorter time to intubation, a higher first-attempt success rate and a reduced incidence of complications. Thus, a rational choice of one of these techniques may be better for the perioperative safety of thyroid tumor patients with a difficult airway.

Comparison of GlideScope Videolaryngoscopy to Direct Laryngoscopy for Intubation of a Pediatric Simulator by Novice Physicians

Objective. To compare novice clinicians' performance using GlideScope videolaryngoscopy (GVL) to direct laryngoscopy (DL). Methods. This was a prospective, randomized crossover study. Incoming pediatric interns intubated pediatric simulators in four normal and difficult airway scenarios with GVL and DL. Primary outcomes included time to intubation and rate of successful intubation. Interns rated their satisfaction of the devices and chose the preferred device. Results. Twenty-five interns were included. In the normal airway scenario, there were no differences in mean time for intubation with GVL or DL (61.4 versus 67.4 seconds, P = NS) or number of successful intubations (19 versus 18, P = NS). In the difficult airway scenario, interns took longer to intubate with GVL than DL (87.7 versus 61.3 seconds, P = 0.018), but there were no differences in successful intubations (14 versus 15, P = NS). There was a trend towards higher satisfaction for GVL than DL (7.3 versus 6.4, P = NS), and GVL was chosen as the preferred device by a majority of interns (17/25, 68%). Conclusions. For novice clinicians, GVL does not improve time to intubation or intubation success rates in a pediatric simulator model of normal and difficult airway scenarios. Still, these novice clinicians overall preferred GVL.

The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.

A systematic review of the role of videolaryngoscopy in successful orotracheal intubation

BACKGROUND

The purpose of our study was to organize the literature regarding the efficacy of modern videolaryngoscopes in oral endotracheal intubation, then perform a quality assessment according to recommended external criteria and make recommendations for use.

METHODS

Inclusion criteria included devices with recent studies of human subjects. A total of 980 articles were returned in the initial search and 65 additional items were identified using cited references. After exclusion of articles failing to meet study criteria, 77 articles remained. Data were extracted according to the rate of successful intubation and improvement of glottic view compared with direct laryngoscopy. Studies were classified according to whether they primarily examined subjects with normal airways, possessing risk factors for difficult direct laryngoscopy, or following difficult or failed direct laryngoscopy.

RESULTS

The evidence of efficacy for videolaryngoscopy in the difficult airway is limited. What evidence exists is both randomized prospective and observational in nature, requiring a scheme that evaluates both forms and allows recommendations to be made.

CONCLUSIONS

In patients at higher risk of difficult laryngoscopy we recommend the use of the Airtraq, CTrach, GlideScope, Pentax AWS and V-MAC to achieve successful intubation. In difficult direct laryngoscopy (C&L >/= 3) we cautiously recommend the use of the Airtraq, Bonfils, Bullard, CTrach, GlideScope, and Pentax AWS, by an operator with reasonable prior experience, to achieve successful intubation when used in accordance with the ASA practice guidelines for management of the difficult airway. There is additional evidence to support the use of the Airtraq, Bonfils, CTrach, GlideScope, McGrath, and Pentax AWS following failed intubation via direct laryngoscopy to achieve successful intubation. Future investigation would benefit from precise qualification of the subjects under study, and an improvement in overall methodology to include randomization and blinding.

Standard clinical risk factors for difficult laryngoscopy are not independent predictors of intubation success with the GlideScope

STUDY OBJECTIVES

To determine whether the first-attempt tracheal intubation incidence using the GlideScope videolaryngoscope is higher in patients with predicted increased risk of difficult laryngoscopy, and to assess the ability of other a priori defined standard risk factors to predict first-attempt intubation success, in aggregate and by forming scores.

DESIGN

Prospective study.

SETTING

Operating room in a tertiary-care academic center.

PATIENTS

357 patients intubated with the GlideScope for nonemergent general anesthesia.

INTERVENTIONS AND MEASUREMENTS

Mallampati airway class was used to create two groups of patients, one with higher and the other, lower, potential difficult laryngoscopy (Mallampati classes 3-4 and 1-2, respectively). Intubation success on the first attempt with the GlideScope videolaryngoscope in patients with a Mallampati class 3 or 4 airway versus those with Mallampati class 1 or 2 airway was tested. We also evaluated the predictive ability of the Mallampati airway class (1 and 2 vs 3 and 4) along with 9 other possible predictors of difficult intubation on first-attempt intubation success: gender, age, body mass index, level of training within our anesthesia residency program (Clinical Anesthesia Resident years 1, 2, and 3), ASA physical status, mouth opening, thyromental distance, neck flexion, and neck extension.

MAIN RESULTS

None of the standard predictors of difficult intubation was significantly associated with outcome after adjusting for other predictors. A multivariable model containing the aggregate set of variables predicted outcome significantly better than a risk score formed as the sum of 10 predictors ("Risk 10"; P = 0.0176).

CONCLUSIONS

With GlideScope-assisted tracheal intubation, Mallampati airway class is not an independent risk factor for difficult intubation. Other standard clinical risk factors of difficulty with direct laryngoscopy also do not appear to be individually predictive of first-attempt success of tracheal intubation.

GlideScope videolaryngoscope vs. Macintosh direct laryngoscope for intubation of morbidly obese patients: a randomized trial

BACKGROUND

Morbidly obese patients are at increased risk of hypoxemia during tracheal intubation because of increased frequency of difficult and impossible intubation and a decreased apnea tolerance. In this study, intubation with the GlideScope videolaryngoscope (GS) was compared with the Macintosh direct laryngoscope (DL) in a group of morbidly obese patients.

METHODS

One hundred consecutive patients (body mass index ≥ 35 kg/m(2) ) scheduled for bariatric surgery were randomized 1 : 1 to intubation with GS (group GS) or DL (group DL). The primary outcome was intubation time. Secondary outcomes were number of attempts, Cormack-Lehane grade, intubation difficulty scale score (IDS), subjective difficulty of intubation, desaturation, airway bleeding, postoperative sore throat, and hoarseness. Group assignment was not blinded.

RESULTS

Intubation in group GS and group DL lasted 48 (22-148) and 32 s (17-209), respectively (median (range); P = 0.0001); median difference 11 s (95% confidence interval 6-17). Laryngoscopic views were better in group GS with Cormack-Lehane grades 1/2/3/4 distributed as 35/13/2/0 vs. 23/13/10/4 in group DL (P = 0.003). IDS scores were significantly lower with GS than with DL. No other statistically significant differences were found. Two cases of failed intubation occurred in group DL vs. none in group GS (non-significant). Both patients were intubated with the GlideScope without problems.

CONCLUSION

Intubation of morbidly obese patients with GS was slightly slower than with DL. The increased intubation time was of no clinical consequence as no patients became hypoxemic. Both devices generally performed well in the studied population, but the GS provided better laryngoscopic views and decreased IDS scores.

A comparison of GlideScope(®) videolaryngoscopy and direct laryngoscopy for nasotracheal intubation in children

BACKGROUND

The relative effectiveness of GlideScope(®) videolaryngoscopy (GV) for nasotracheal intubation in pediatric patients is unclear. The purpose of this study is to evaluate the usefulness of GV for nasotracheal intubation compared with direct laryngoscopy (DL) in pediatric patients.

METHODS

Our patient cohort consisted of 80 children <10 years of age who required nasotracheal intubation for elective dental or facial surgery. The patients were randomly allocated to GV (n = 40) or DL (n = 40) group. The time to intubation (TTI), glottic view grade, frequency of Magill forceps use, and degree of difficulty in intubation were evaluated.

RESULTS

The median TTI was similar between the groups. The TTI of the former 20 patients was faster in the DL group (53.3 s, interquartile range: 42.0-64.3) than GV group (65.9 s, interquartile range: 56.0-93.9) (P = 0.007), whereas the TTI of the latter 20 patients was comparable between the groups. There were no significant differences in glottic view grade, frequency of Magill forceps use, and degree of difficulty in intubation between the two groups.

CONCLUSIONS

GV can provide similar intubation performance characteristics compared with DL when used for nasotracheal intubation in pediatric patients. However, experience is needed to be skillful in the GV to acquire comparable TTI with DL.